// Copyright 2018 The Flutter team. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('flutter demo'),
        ),
        body: HomePage(),
      ),
      theme: ThemeData(primarySwatch: Colors.yellow),
    );
  }
}

//自定义有状态组件
class HomePage extends StatefulWidget {
  HomePage({Key? key}) : super(key: key);

  @override
  State<HomePage> createState() => _HomePageState();
}

class _HomePageState extends State<HomePage> {
  int countNum = 0;
  @override
  Widget build(BuildContext context) {
    return Column(
      children: <Widget>[
        SizedBox(
          height: 200,
        ),
        Chip(label: Text("${this.countNum}")),
        SizedBox(
          height: 20,
        ),
        RaisedButton(
          onPressed: () {
            setState(() {
              //只有状态组件才有
              this.countNum++;
            });
          },
          child: Text("按钮"),
        )
      ],
    );
  }
}
